Hitherto, electrochromic devices (hereinafter referred to as “EC devices”) have been known as devices such as light adjusters having a light adjusting capability of enabling the transmissivity to be freely adjusted (hereinafter referred to as “light adjusting devices”). Such an EC device is, for example, made from a material that undergoes a spectral change upon an electrochemical redox reaction, such as tungsten oxide or prussian blue, and controls the transmitted light by absorbing light. However, because such an EC device is current driven, if the EC device is made to have a large area, then a large voltage drop arises, the response speed drops markedly, and degradation of constituent materials due to electrochemical changes and so on occurs during prolonged passing of a current; such an EC device thus cannot be used as a light adjuster that is required to be durable.
In recent years, voltage driven light adjusting devices have thus been used in a laminated glass instead of such current driven EC devices. For example, nematic curvilinear aligned phase (NCAP) liquid crystal light adjusters are known as such voltage driven light adjusting devices. Such a nematic liquid crystal light adjuster is made from a liquid crystal material, and has excellent durability, and can easily be made to have a large area (see, for example, Japanese Laid-Open Patent Publication (Kohyo) No. S58-501631).
As shown in FIG. 3, in general, such a light adjuster 30 is comprised of a liquid crystal layer 33 having a light adjusting function in which a plurality of voids 31 are filled with nematic liquid crystalline rod-like molecules 32 (hereinafter referred to as “liquid crystal molecules”), and a pair of PET films 34 that sandwich the liquid crystal layer 33 therebetween; transparent electrically conductive films 35 are provided on facing surfaces of the PET films 34 so as to be bonded to the liquid crystal layer 33, and a voltage is applied to the liquid crystal layer 33 via this pair of transparent electrically conductive films 35. The liquid crystal layer 33 is formed of a transparent polymer film 36 having a plurality of voids 31 therein, and each void 31 is filled with liquid crystal molecules 32 so as to form a liquid crystal capsule 37.
According to this light adjuster 30, when a voltage is not being applied, the liquid crystal molecules 32 line up along the curved wall surfaces of the liquid crystal capsules 37, and are thus not arranged along the direction of travel of light transmitted through the liquid crystal capsules 37; the optical path of the transmitted light thus meanders around, and incident light is scattered at boundary layers between the liquid crystal capsules 37 and the polymer film 36, and hence the liquid crystal layer 33 becomes cloudy. On the other hand, when a voltage is applied, the liquid crystal molecules 32 line up along the direction of the electric field produced. At this time, if the liquid crystal layer 33 is made from a material such that the ordinary refractive index no of the liquid crystal molecules 32 matches the refractive index np of the polymer film 36, it becomes such that boundary layers between the liquid crystal capsules 37 and the polymer film 36 do not exist optically, and hence light incident on the liquid crystal layer 33 can be transmitted unhindered, whereby the liquid crystal layer 33 becomes transparent.
Due to the above principle, the light adjuster 30 has a visual field controlling capability of shutting off the visual field through scattering of incident light when a voltage is not being applied, and securing the visual field through allowing incident light to be transmitted unhindered when a voltage is being applied.
As shown in FIG. 4, the light adjuster 30 has an electrode structure provided at one end of the light adjuster 30 where the liquid crystal layer 33, the transparent electrically conductive film 35a and the PET film 34a are partially cut off, and is comprised of a silver paste 40 applied on an exposed part of the transparent electrically conductive film 35b, and a pin connector 41 that is pressed onto the upper surface of the silver paste 40. The pin connector 41 has an extension 41a which extends in the form of a tongue, and a lead wire 43 is coupled to the extension 41a by solder 42 (see, for example, Japanese Utility Model Application Publication (Kokoku) No. H6-37395).
The electrode structure of the light adjuster 30 is exposed to the outside since it is not covered by the PET film 34a as described above. With this electrode structure, when the light adjuster 30 is used in a laminated glass and is fitted into a window frame, the electrode structure is swallowed into a sash or the like, and thus it was conventionally considered that there is no necessity to cover the light adjuster 30 with a glass sheet or the like of the laminated glass. However, recently, from the view point of improving handleability of a laminated glass using the light adjuster 30 when mounting the glass into a window frame, there is a demand for covering this electrode structure with a glass sheet or the like.
However, in the above described electrode structure, the total thickness of the parts which need to be covered by a glass sheet or the like, that is, the silver paste 40 and the pin connector 41, is less than the total thickness of the liquid crystal layer 33, the PET film 34a and the transparent electrically conductive film 35a. Due to this, when preparing a laminated glass, stress due to the pushing pressure on the glass sheet is concentrated on the part of the light adjuster where the transparent electrically conductive film 35a and the PET film 34a are partially cut off. Consequently, the transparent electrically conductive film 35a and the PET film 34a are bent toward the transparent electrically conductive film 35b and the PET film 34b, causing the transparent electrically conductive film 35a and the transparent electrically conductive film 35b to contact each other and electrically short-circuit. As a result, there is a problem that operation failure occurs with the light adjuster 30.
The present invention has been devised in view of the above-described problems, and it is an object of the present invention to provide a light adjuster and a laminated glass which are capable of improving handleability thereof and prevent the occurrence of operation failure of the light adjuster.